Clinical practice guideline on diagnosis and treatment of hyponatraemia

Abstract

Hyponatraemia, defined as a serum sodium concentration <135 mmol/l, is the most common disorder of body fluid and electrolyte balance encountered in clinical practice. It can lead to a wide spectrum of clinical symptoms, from subtle to severe or even life threatening, and is associated with increased mortality, morbidity and length of hospital stay in patients presenting with a range of conditions. Despite this, the management of patients remains problematic. The prevalence of hyponatraemia in widely different conditions and the fact that hyponatraemia is managed by clinicians with a broad variety of backgrounds have fostered diverse institution- and speciality-based approaches to diagnosis and treatment. To obtain a common and holistic view, the European Society of Intensive Care Medicine (ESICM), the European Society of Endocrinology (ESE) and the European Renal Association - European Dialysis and Transplant Association (ERA-EDTA), represented by European Renal Best Practice (ERBP), have developed the Clinical Practice Guideline on the diagnostic approach and treatment of hyponatraemia as a joint venture of three societies representing specialists with a natural interest in hyponatraemia. In addition to a rigorous approach to methodology and evaluation, we were keen to ensure that the document focused on patient-important outcomes and included utility for clinicians involved in everyday practice.

Thiazide-Associated Hyponatremia, Report of the Hyponatremia Registry: An Observational Multicenter International Study

“…The high number of patients (773) who were erroneously diagnosed with SIADH by their treating physicians despite overt signs of hypovolemia and subsequently their exclusion after adjudication from the primary analysis group underline the need for a thorough diagnostic work-up. However, the recommended set of laboratory tests [23,24,25,26] including the Schwartz-Bartter criteria as well as cortisol and TSH were performed in only about 20% of all patients in either group. These findings demonstrate that the potentially deleterious impact of this disorder is often not appreciated and that the diagnostic management of hyponatremia in general is poor as has been shown repeatedly in the past [21,27].…”

“…Beyond its importance in determining the correct diagnosis, thiazide discontinuation constitutes the mainstay of TAH treatment [25,26]. However, in 30% of TAH patients, the thiazide was continued throughout the hospital stay and in 13%, cessation was delayed by several days.…”

“…Under these circumstances, the ensuing deterioration of osmotic homeostasis is often severe and potentially life threatening [10,12]. Hence, TAH should always be treated promptly even in mild or moderate cases in order to prevent progression [25,26]. To this end, eliminating the trigger by withdrawing the thiazide diuretic as early as possible is key to effective treatment.…”

“…Concomitant employment of HS can then easily lead to overly rapid correction, as shown here with a reported incidence of 21%. Overly rapid correction can lead to severe neurological sequelae including osmotic demyelination syndrome (ODS), and more recent guidelines advocate lower limits than the ones used in this analysis [25,26]. Had we used these newer limits, an even higher rate of overly rapid correction would probably have been assessed.…”

“…In conclusion, despite the high prevalence of hyponatremia [29,30,31] and published guidance on its diagnosis and treatment [25,26], numerous shortcomings in current management of hyponatremia in general and TAH in particular are evident. Although many highly significant differences exist with regard to clinical and biochemical characteristics, we could not identify a specific diagnostic strategy that reliably distinguished TIH from SIADH.…”